Im thinking of chopping down the cassette and experimenting with different gears. I went around google trying to find some cog/spacer widths but came up with lots of mixed results. Lets say I were to take off the top 3 and the one after that, how many spacers would I need.
probably six, by taking the top three off you would already have three of them so if you took apart an old cassette and took three more from that then you should be fine